The Wall by John Lanchester is an eco-dystopian novel set in the near future, this is a dark and mesmerising vision of what happens when borders become walls, when the world is divided into ‘us’ and ‘others’, and when the young despise the old for what they allowed to happen on their watch.

In an event referred to as ‘the Change’, Sea levels have risen high enough to change coastlines and land masses around the world, displacing countless people. In Britain, a wide concrete wall 10,000 miles long has been built around the edge of the country, both to ward off the water and to keep out refugees – known as ‘the Others’. Kavanagh is a young defender doing a futuristic version of national service: his generation of men and women are each required to defend the Wall for two years, where their hard-won military skills may or may not be enough to keep them alive.

The book has a slow, uncomfortable start, echoing narrator Kavanagh’s painful days embarking on his tour of duty. It is cold, and his shifts are 12 hours on, 12 hours off, with night shifts almost unbearable. Time passes unbelievably slowly on the Wall, where there is nothing to see but ‘concreteskywaterwind’ or ‘skywindconcretewater’.

We are treated to painstaking definitions of type 1 cold and type 2 cold, and by the time the word ‘concrete’ has been repeated about 50 times in a row we have definitely got the point. Kavanagh and his fellow Defenders are sometimes allowed home on leave, and readers are afforded a glimpse of life within the country’s perimeter – there are pubs, trains, B&Bs, parents going about their suburban lives watching old movies of children playing on beaches, and a group of politicians and high status individuals known as The Elite whose ranks the ambitious Kavanagh is desperate to join.

This world is unsettlingly different from ours, but with enough similarities to make it feel realistic. No one wants to bring children into such a world, so those that choose to do so are called Breeders and are given special privileges. Food is scarce and limited to what locals can grow or forage – turnips, mutton and cabbages. Exotic meals are enjoyed only via nostalgic TV cookery shows.

John Lanchester is a financial journalist and author of the hugely enjoyable Capital, which followed the residents of a prosperous South London street who were profiting, or not, from the housing price boom. In this new novel he also reflects our own time by taking two other massive preoccupations – immigration and climate change – and in the tradition of dystopian fiction has extrapolated these into a pretty bleak tale.

It is worth persevering with the book because the action definitely hots up. The training exercises Kavanagh and his team are put through prepare them for a night when the Wall comes under attack. For every ‘Other’ that successfully gets in to the country, one Defender is effectively put to death. Luckily they do well, are decorated, and sent for their next tour of duty to the North, reputedly a safer place to defend, being further from the southern origins of the migrants who will do anything to scale the Wall. As they have been warned, Low Risk also means High Risk, and when the inevitable happens, events start to unspool out of Kavanagh’s control.

[spoiler alert]

‘They were just Others. But maybe now that I was one of them, they weren’t Others any more. If I was an Other, and they were Others, then perhaps none of us were Others but instead we were a new Us.’

This is a sparsely written, often poetic book that is largely lacking in comfort or hope. There is a love story of sorts, a little milky trickle of human kindness, and a slightly perplexing ending. It makes you think though, and that has to be a good thing.

The Wall by John Lanchester is published by Faber & Faber, 288 pages.

Other dystopian fiction on Bookstoker: The Handmaid’s Tale by Margaret Atwood.